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/*
* Copyright (C) 2016 Kaspar Schleiser <kaspar@schleiser.de>
*
* This file is subject to the terms and conditions of the GNU General Public
* License v2. See the file LICENSE for more details.
*/
#define UHCP_MCAST_ADDR "ff15::ABCD"
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <netdb.h>
#include <net/if.h>
#include <arpa/inet.h>
#include "net/uhcp.h"
char _prefix[16];
unsigned _prefix_len;
static const char *BIND_OPTION = "--bind-to-device";
static void bind_to_device(int sock, const char *interface);
int ipv6_addr_split(char *addr_str, char seperator, int _default)
{
char *sep = addr_str;
while(*++sep) {
if (*sep == seperator) {
*sep++ = '\0';
if (*sep) {
_default = atoi(sep);
}
break;
}
}
return _default;
}
int main(int argc, char *argv[])
{
unsigned ifindex;
unsigned _bind_to_device = 0;
if (argc < 3) {
fprintf(stderr, "usage: uhcpd <interface> <prefix/prefix_length> [%s]\n",
BIND_OPTION);
exit(1);
}
ifindex = if_nametoindex(argv[1]);
if (!ifindex) {
fprintf(stderr, "error: invalid interface \"%s\"\n", argv[1]);
exit(1);
}
_prefix_len = ipv6_addr_split(argv[2], '/', 64);
if ((!inet_pton(AF_INET6, argv[2], _prefix)) || (_prefix_len > 128)) {
fprintf(stderr, "error: cannot parse prefix\n");
exit(1);
}
if (argc == 4) {
if (strcmp(BIND_OPTION, argv[3])) {
fprintf(stderr, "error: unkwown option\n");
exit(1);
}
_bind_to_device = 1;
}
char *addr_str = UHCP_MCAST_ADDR;
struct addrinfo hint;
memset(&hint, 0, sizeof(hint));
hint.ai_family = AF_INET6;
hint.ai_socktype = SOCK_DGRAM;
hint.ai_protocol = IPPROTO_UDP;
hint.ai_flags |= AI_NUMERICHOST;
struct addrinfo *mcast_addr;
int res = getaddrinfo(addr_str, UHCP_PORT_STR,
&hint, &mcast_addr);
if (res != 0) {
perror("getaddrinfo()");
exit(1);
}
int sock = socket(mcast_addr->ai_family, mcast_addr->ai_socktype,
mcast_addr->ai_protocol);
if (sock < 0) {
perror("socket() failed");
exit(1);
}
if (_bind_to_device) {
bind_to_device(sock, argv[1]);
}
if (bind(sock, mcast_addr->ai_addr, mcast_addr->ai_addrlen) < 0) {
perror("bind() failed");
exit(1);
}
/* join multicast group */
struct ipv6_mreq mreq;
memcpy(&mreq.ipv6mr_multiaddr,
&((struct sockaddr_in6 *)mcast_addr->ai_addr)->sin6_addr,
sizeof(struct in6_addr));
mreq.ipv6mr_interface = ifindex;
puts("Joining IPv6 multicast group...");
if (setsockopt(sock, IPPROTO_IPV6, IPV6_JOIN_GROUP,
&mreq, sizeof(mreq)) < 0) {
perror("setsockopt(IPV6_JOIN_GROUP) failed");
exit(1);
}
freeaddrinfo(mcast_addr);
char buf[2048];
struct sockaddr_in6 src_addr;
unsigned n = sizeof(src_addr);;
puts("entering loop...");
while(1) {
int nbytes = recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr*)&src_addr, &n);
if (nbytes < 0) {
perror("recvfrom() failed");
continue;
}
uhcp_handle_udp((uint8_t *)buf, nbytes, (uint8_t *)&src_addr.sin6_addr, ntohs(src_addr.sin6_port), ifindex);
}
close(sock);
exit(0);
}
int udp_sendto(uint8_t *buf, size_t len, uint8_t *dst, uint16_t dst_port, uhcp_iface_t iface)
{
struct sockaddr_in6 dst_addr;
memset(&dst_addr, '\0', sizeof(dst_addr));
dst_addr.sin6_family = AF_INET6;
memcpy(&dst_addr.sin6_addr, dst, 16);
dst_addr.sin6_port = htons(dst_port);
dst_addr.sin6_scope_id = iface;
int fd = socket(AF_INET6, SOCK_DGRAM, 0);
if (fd == -1) {
perror("creating send socket");
return -1;
}
ssize_t res;
if ((res = sendto(fd, buf, len, 0, (struct sockaddr *)&dst_addr, sizeof(dst_addr))) == -1) {
perror("udp_sendto(): sendto()");
}
close(fd);
return res;
}
/* Requires to be 'root', I didn't find another solution for the moment */
static void bind_to_device(int sock, const char *interface)
{
if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE,
interface, IF_NAMESIZE) < 0 ) {
perror("setsockopt(SO_BINDTODEVICE) failed");
exit(1);
}
}